|St. Theophan the Recluse|
That being said, there seems at times to be a quality to his spirituality that suggests a less meek and gentle side to him—or, at least, to his understanding of the Christian life. One of his quotations in the Wikipedia article linked above, for example, states, "A Christian without zeal is a poor Christian."
Is it possible to be a truly spiritual person and zealous? The word "zeal" implies a narrowness of mind, an almost obsessive fixation with an object, person, or cause. It denotes ardor and an unwillingness to be deterred, which can morph into blind prejudice. Zeal as a spiritual quality is very much not in keeping with the quintessential description of Christian spirituality found in Galatians 5:22-23. Zeal is hardly peaceful, generous, kind, or patient. When one thinks of Christian zeal, the Crusades come to mind, which ae not among our finer moments as a people of faith.
Wiktionary defines "zeal" (here) as, "The fervor or tireless devotion for a person, cause, or ideal and determination in its furtherance; diligent enthusiasm; powerful interest." Although less objectionable than the "feel" of the term, there still seems to be elements of questionable spirituality. Faith is not passionless, but faith's passion is less self-involved and fixated than seems to be the case with zeal even at its best. Can one be a faithful follower of Christ and also a zealous one? The answer is not certain but seems to be, "In theory, possibly,'Yes,' but in practice, more likely, 'No.'"